Indicators, such as light indicators, are generally used in factory automation to indicate the operating status of a machine. An example of these light indicators are often called POST LIGHTS™ or STACKLIGHTS™. The name refers to the configuration of the light indicator since it usually includes a plurality of colored light sources stacked one on top of the other in a post formation. For example, the indicator may consist of a red light stacked on top of a yellow light stacked on top of a green light, similar to a traffic semaphore. These indicators illuminate depending on an input signal supplied to the indicator. This type of indicator is generally mounted high on a machine to indicate whether it is running, stopped, or in a trouble condition.
Typically, the lights in the indicator are illuminated by supplying a voltage to each light, causing the light to remain lit for as long as the voltage continues to be applied to the light. Many of these light indicators are hardwired to include a flasher for causing one or more of the lights to flash. The wiring is typically located inside the device and is not changed during operation.
These types of light indictors have disadvantages. One such disadvantage is that an electrician is required to wire them. Another such disadvantage is that the lights are usually quite large. Therefore, improvements are desirable.